Answer:
- after week 7: 4374 pennies
- 486 pennies: after week 5
Step-by-step explanation:
The sequence values have a first term of 6 and a common ratio of 3, so can be described by the formula ...
an = 6·3^(n-1)
This can be rearranged to ...
an = 2·3^n
__
When n=7, the value is ...
a7 = 2·3^7 = 4374 . . . . pennies saved after 7 weeks
__
To find when there are 486 pennies saved, we can solve the equation ...
486 = 2·3^n
243 = 3^n
log(243) = n·log(3) . . . . . . . take the logarithm
log(243)/log(3) = n = 5 . . . . divide by the coefficient of n
Tabitha will have saved 486 pennies after 5 weeks.
<em>x</em>² - x
<em>x</em> = 4
4² - 4
16 - 4 = 12
Hope this helps!
Answer:
For x = 10:
For y = - 3:
Step-by-step Explanation:
Before we start let's recall the formula for the linear equations.
So first let's solve for x=10:
Move 10 to the other side.
As there is no y given we will simply write 0y.
Now let's solve for y=-3:
Move -3 to the other side.
As there is no x given we will simply write 0x.
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Answer:
403.75
Step-by-step explanation:
we can write the following equation
.75m+145=price
we just need to plug in 345 for m
.75*345+145=price
put this into a calculator and get 403.75
Answer:
12, 13, 14
Step-by-step explanation:
Denote the integers as:
x
x+1
x+2
The sum of their squares, so that would be;
(x^(2)) + (( x + 1 )^(2)) + (( x + 2 )^(2)) = 509
write out the squares
x^2 + x^2 + 2x + 1 + x^2 + 4x + 4 = 509
combine like terms
3x^2 + 6x + 5 = 509
inverse operations
3x^2 + 6x + 5 = 509
-5 -5
3x^2 + 6x = 504
factor
3x^2 + 6x = 504
3 ( x^2 + 2x ) =504
Inverse operations
3 ( x^2 + 2x ) = 504
/3 /3
x^2 + 2x = 168
Factor again
x ( x + 2 ) = 168
At this point, it should be obvious that x is 12 (because 12 * 14 = 168)
So now substitute back into the consecutive numbers
x = 12
x + 1 = 13
x + 2 = 14
